Biological upgrading of hydrocarbon streams with nickel-binding proteins

Abstract

Nickel-binding proteins and methods of biologically upgrading hydrocarbon streams, such as crude oil, using nickel-binding proteins are provided herein. The nickel-binding proteins can be used to remove impurities such as metals and/or asphaltenes from a hydrocarbon stream. In some cases, the nickel-binding proteins can be chemically or genetically modified and can be used in different locations such as petroleum wells, pipes, reservoirs, tanks and/or reactors.

1 . A method of biologically upgrading a hydrocarbon stream comprising contacting the hydrocarbon stream with a nickel-binding protein (NBP). 
     
     
         2 . The method of  claim 2 , wherein the nickel-binding protein is substantially cell-free. 
     
     
         3 . The method of  claim 1 , wherein the nickel-binding protein is a recombinant protein. 
     
     
         4 . The method of  claim 1 , wherein the nickel-binding protein classifies as belonging to at least one Pfam family selected from the group consisting of PF01155, PF02492, PF00254, PF05194, PF00903, and PF08753. 
     
     
         5 . The method of  claim 1 , wherein the nickel-binding protein has at least 85% sequence identity to a polypeptide selected from the group consisting of SEQ ID NOs: 1-8. 
     
     
         6 . The method of  claim 1 , wherein the biological upgrading comprises removing impurities from the hydrocarbon. 
     
     
         7 . The method of  claim 6 , wherein the impurities comprise nickel, cadmium, vanadium, or arsenic. 
     
     
         8 . The method of  claim 7 , wherein the metal is nickel or vanadium. 
     
     
         9 . The method of  claim 1 , wherein the hydrocarbon stream is crude oil or vacuum residual. 
     
     
         10 . The method of  claim 1 , wherein the contacting is performed at a temperature from about 15° C. to about 90° C. 
     
     
         11 . The method of  claim 1 , wherein the nickel-binding protein is thermally stable from about 90° C. to about 120° C. 
     
     
         12 . The method of  claim 1 , further comprising selecting one or more nickel-binding protein for the contacting step based upon impurity type and content in the hydrocarbon stream. 
     
     
         13 . The method of  claim 1 , wherein there is less than 10% (wt/wt) loss of hydrocarbon following separating the impurities from the hydrocarbon stream. 
     
     
         14 . The method of  claim 1 , further comprising contacting the hydrocarbon stream with an oxygenase, a NBP and/or another NBP. 
     
     
         15 . The method of  claim 1 , wherein the nickel-binding protein is present in an oil reservoir, a pipeline, a tank, a vessel, a reactor, and/or a waste water stream. 
     
     
         16 . The method of  claim 1 , wherein the nickel-binding protein is in free form, crystal form, and/or immobilized on a carrier. 
     
     
         17 . The method of  claim 16 , wherein the carrier is selected from the group consisting of a membrane, a filter, a matrix, diatomaceous material, particles, beads, an ionic liquid, an electrode, a mesh, and a combination thereof. 
     
     
         18 . The method of  claim 17 , wherein the matrix comprises an ion-exchange resin, a polymeric resin and/or a water wet protein. 
     
     
         19 . The method of  claim 17 , wherein the particles and/or beads comprise a material selected from the group consisting of glass, ceramic, and a polymer. 
     
     
         20 . The method of  claim 1 , wherein the nickel-binding protein is hydrophobically modified to be at least 10% more enriched in hydrophobic amino acids selected from the group consisting of Ala, Gly, Ile, Leu, Met, Pro, Phe, and Trp. 
     
     
         21 . The method of  claim 20 , wherein the nickel-binding protein is selected from the group consisting of SEQ ID NOs: 1-8. 
     
     
         22 . The method of  claim 20 , wherein the enrichment is at least 20%. 
     
     
         23 . The method of any one of  claim 20 , wherein enrichment is achieved by replacing a native residue with a hydrophobic amino acid. 
     
     
         24 . The method of  claim 20 , wherein enrichment is achieved by adding a hydrophobic amino acid between two native residues. 
     
     
         25 . The method of  claim 1 , wherein the nickel-binding protein is rinsed with n-propanol. 
     
     
         26 . The method of  claim 1 , wherein the nickel-binding protein is conjugated to a polyethylene glycol. 
     
     
         27 . The method of  claim 1 , wherein disulfide bridges are added to the nickel-binding protein. 
     
     
         28 . The method of  claim 1 , wherein one to ten hydrophobic amino acids are added to an amino or carboxy terminus of the nickel-binding protein, wherein the hydrophobic amino acid is selected from the group consisting of Ala, Gly, Ile, Leu, Met, Pro, Phe, and Trp. 
     
     
         29 . A recombinant polypeptide having at least 70% sequence identity but no more than 90% sequence identity to any one of SEQ ID NOs: 1-8, wherein the sequence is manipulated to be at least 10% more enriched in hydrophobic amino acids relative to the sequence selected from SEQ ID NOs: 1-8, and wherein the hydrophobic amino acids are selected from the group consisting of Ala, Gly, Ile, Leu, Met, Pro, Phe, and Trp. 
     
     
         30 . The recombinant polypeptide of  claim 29 , wherein the enrichment is at least 20%. 
     
     
         31 . An isolated or recombinant nucleic acid molecule comprising a sequence encoding the polypeptide of  claim 29 . 
     
     
         32 . A vector comprising the nucleic acid molecule of  claim 31 .